1. Field of the Invention
The present invention relates to a sheet processing apparatus suitably adapted to an inkjet printing apparatus and enabling to apply heat to a sheet with high efficiency.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2004-306589 discusses an inkjet printing apparatus including a heater for drying ink. In this apparatus, a sheet printed by the inkjet printing apparatus is irradiated with ultraviolet rays to cure light curing ink, and is subject to pressure contact and heat by a roller with a built-in heater to fix the ink in a short time.
In the apparatus configuration in Japanese Patent Application Laid-Open No. 2004-306589, heat is mainly transferred from a narrow line-shaped region in which the roller and a surface of the sheet come into contact with each other. Therefore, the transfer efficiency of heat energy of the heater is poor, so that a large output heater is needed to dry the sheet in a short time. In other words, the power consumption of the printing apparatus uselessly increases.
Further, a lot of time may be required to dry the ink, depending on a type of a used sheet or ink. In such a case, the apparatus in Japanese Patent Application Laid-Open No. 2004-306589 has a possibility in which the ink adhering onto the surface of the heating roller cannot be dried during one revolution and is re-transferred to the sheet.
Further, when the used sheet is a thin paper, a cloth, or plastics, which has low rigidity, the print quality may be decreased by generating fine crease or corrugation on the sheet due to heating.